Motor control method, control unit and computer program product
By acquiring motor speed and torque in real time and dynamically calculating the thermal protection temperature threshold based on pre-stored relationships, the overheating problem of the electric drive system under different operating conditions is solved, achieving optimal thermal protection for the motor and improved system stability.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- BOSCH AUTOMOTIVE PRODUCTS (CHANGSHA) CO LTD
- Filing Date
- 2024-12-03
- Publication Date
- 2026-06-05
Smart Images
Figure CN122159761A_ABST
Abstract
Description
Technical Field
[0001] This application relates to motor control methods, and more particularly to a motor control method suitable for electric drive systems, as well as related control units and computer program products. Background Technology
[0002] Electric drive systems are widely used in vehicles, industrial equipment, and other applications. For example, wiper motors (also called drive motors) are frequently used in motor vehicles such as automobiles, serving as a common power source for windshield wipers. When the wiper is in operation, driven by the wiper motor, the wiper arm reciprocates under the control of a controller and through the reduction gear (usually a worm gear mechanism), driving the wiper blades to perform the desired wiping action to clear rain, snow, or dust from the vehicle's windshield, thus ensuring the driver has good visibility.
[0003] When windshield wipers operate for extended periods or undergo prolonged dry wiping or other adverse conditions, overheating and overload can easily occur in the electric drive system's motor or other critical components. This can affect the normal operation of the wipers and endanger the lives of the driver and other occupants. Therefore, windshield wiper safety protection is crucial. In particular, thermal protection for the motor and other critical components is one of the important measures to ensure the reliability of motor operation.
[0004] Therefore, in the known prior art, thermal protection measures are usually provided in electric drive systems, and corresponding motor control methods are adopted. These methods can control the operation of the drive motor of the electric drive system based on a predetermined thermal protection temperature threshold. This is to trigger a thermal protection mechanism (which is implemented, for example, in software and / or hardware) when the temperature of a selected component of interest in the electric drive system exceeds the thermal protection temperature threshold, thereby preventing thermal damage to the selected component of interest due to excessive temperature and providing the required thermal protection function.
[0005] However, in existing known designs, the thermal protection temperature threshold of the electric drive system is usually set to a constant value, which cannot be changed for different operating conditions of the electric drive system in actual operation, and therefore cannot be fully adapted to the actual operating conditions of the electric drive system.
[0006] For example, those skilled in the art know that in the field of vehicles using windshield wipers, for electric drive systems including drive motors, there are significant differences in the load they bear and the acceptable thermal protection temperature threshold under different operating conditions such as dry wiping (wiping under dry conditions) and wet wiping (wiping under wet conditions). For example, under low load and low speed operation during wet wiping, plastic components in the transmission system (e.g., worm gears typically made of plastic that may be selected as a component of interest in thermal protection design) can usually withstand a higher thermal protection temperature threshold. In this case, setting the thermal protection temperature threshold of the electric drive system to a constant value would obviously fail to fully utilize the heat resistance potential of the plastic components. Furthermore, since the thermal protection temperature threshold is set to a constant value, when the temperature of the plastic components approaches the constant thermal protection temperature threshold, adverse phenomena such as repeated changes or irregular fluctuations in wiping speed due to frequent triggering of the thermal protection mechanism can easily occur.
[0007] Therefore, overcoming the shortcomings or defects in the existing technology is a pressing technical problem that needs to be solved. In other words, there is a need to improve upon the currently known technology. Summary of the Invention
[0008] In view of the above background, the purpose of this application is to propose a motor control method that can at least partially or even completely overcome the deficiencies or defects mentioned in the background section (in particular, to propose a motor control method that can adapt to the actual operating conditions of an electric drive system).
[0009] The purpose of this application is also to provide a control unit and computer program product corresponding to the above-mentioned motor control method.
[0010] Therefore, according to one aspect of this application, a motor control method is provided, which can control the operation of the drive motor of an electric drive system based on a predetermined thermal protection temperature threshold to provide the required thermal protection function. The motor control method includes the following steps:
[0011] In response to the start of the drive motor, the temperature of selected components of interest in the electric drive system is acquired; and
[0012] The temperature of the selected component of interest is compared with the thermal protection temperature threshold, and the operating state of the drive motor is changed based on the comparison result. When the temperature of the selected component of interest exceeds the thermal protection temperature threshold, a thermal protection mechanism is triggered to stop the operation of the drive motor or adjust its operating parameters, thereby preventing thermal damage to the selected component of interest due to excessive temperature.
[0013] Specifically, before comparing the acquired temperature of the selected component of interest with the thermal protection temperature threshold, the thermal protection temperature threshold is determined in real time through the following thermal protection temperature threshold determination process, which includes:
[0014] The data acquisition step involves acquiring the speed and torque of the drive motor in real time in response to its startup: and
[0015] A thermal protection temperature threshold determination step, wherein the thermal protection temperature threshold is calculated and determined using the acquired speed and torque of the drive motor and based on a pre-stored predetermined relationship between the speed and torque of the drive motor under different operating conditions and different preset thermal protection temperature thresholds. According to another aspect of this application, a control unit is also proposed, comprising:
[0016] Processor; and
[0017] A memory storing computer programs / instructions, which, when executed by the processor, implement the motor control method as described above.
[0018] According to another aspect of this application, a computer program product is also proposed, which includes a computer program that, when executed by a processor, implements the motor control method as described above.
[0019] As can be seen from the above description, this application provides a novel motor control method and corresponding control unit and computer program product. Its key point or main design concept is that the thermal protection temperature threshold adapted to the electric drive system can be automatically determined using the operating data of the drive motor of the electric drive system. For example, the thermal protection temperature threshold can be automatically calculated based on the predetermined relationship between the speed and torque of the drive motor under different operating conditions and different preset thermal protection temperature thresholds, combined with the speed and torque of the drive motor obtained in real time, thereby obtaining an optimized thermal protection temperature threshold. This can achieve beneficial effects such as enhancing adaptability to the operating environment and actual working conditions, improving the reliability of system operation, and maximizing the heat resistance potential of system components. Attached Figure Description
[0020] The features, advantages, and many other aspects of this application will become clearer from the following more detailed description of the application given with reference to the accompanying drawings and exemplary embodiments, in which:
[0021] Figure 1 This is a flowchart or schematic diagram of the working principle of the process for determining the thermal protection temperature threshold in the motor control method according to an exemplary embodiment of this application.
[0022] Figure 2 This is a schematic diagram illustrating an example of a predetermined relationship between the speed and torque of a pre-stored drive motor used in a motor control method according to an exemplary embodiment of this application.
[0023] Figure 3 This is a schematic diagram illustrating another example of a predetermined relationship between the speed and torque of a pre-stored drive motor used in a motor control method according to an exemplary embodiment of this application.
[0024] Figure 4 This is a schematic diagram illustrating the principle of calculating intermediate coefficients using a pre-stored predetermined relationship between the speed and torque of a drive motor and the speed and torque at any real-time data point in a motor control method according to an exemplary embodiment of this application.
[0025] Figure 5 This is a schematic diagram illustrating the principle of calculating the thermal protection temperature threshold using an intermediate coefficient in a motor control method according to an exemplary embodiment of this application. Detailed Implementation
[0026] The specific embodiments of this application and other details are described in detail below with reference to the accompanying drawings. It should be understood that the embodiments and related descriptions given herein should be construed as exemplary and not as limiting the scope of this application.
[0027] Furthermore, it should be noted that, for the sake of brevity and to facilitate a better understanding of the design points or substantive features of this application, the specification and accompanying drawings of this application focus on describing or illustrating the content related to the main design points or principles of this application, while omitting or simplifying other parts (especially omitting detailed descriptions of techniques known in the art). Regarding the basic principles, control processes, and specific details of these omitted parts, they pertain to known techniques in the art or can be specifically applied by those skilled in the art based on existing knowledge and application environments, and will not be elaborated upon here, nor will they be illustrated in detail. In other words, methods (e.g., control processes) and techniques well-known in the art are not illustrated or described in detail to avoid unnecessarily obscuring the core or substance of this application.
[0028] Furthermore, for ease of understanding and description, the motor control method of this application will be illustrated exemplarily using an electric drive system for windshield wipers (which is widely used in motor vehicles, etc., but not limited thereto) as an example, but this application is obviously not limited thereto. In other words, the motor control method of this application can also be applied to other drive systems.
[0029] To facilitate a clearer understanding of the various aspects of this application, before describing the technical solutions of this application, we will first briefly describe the main problems or defects of the existing known electric drive systems for wipers in terms of motor control and determination of thermal protection temperature thresholds.
[0030] As mentioned above, in the known prior art, electric drive systems are typically equipped with thermal protection measures and employ corresponding motor control methods. These methods can control the operation of the drive motor of the electric drive system based on a predetermined thermal protection temperature threshold. This is to trigger the thermal protection mechanism (i.e., take corresponding measures, such as detecting the temperature of the selected component of interest; when the temperature exceeds the thermal protection temperature threshold, the speed of the drive motor in the electric drive system can be appropriately reduced; and when the temperature drops to or below the thermal protection temperature threshold, the speed of the drive motor can be appropriately increased as needed, but not limited thereto) to prevent the selected component of interest from being thermally damaged due to excessive temperature.
[0031] It has been found that, in some cases, the thermal protection bottleneck of an electric drive system lies primarily in its transmission system. Specifically, for example, in electric drive systems used for windshield wipers, worm gear mechanisms are typically used as their reduction gears, and the power transmission between the worm gear (usually made of plastic, and thus often referred to in the art as a "white gear") and the worm (usually made of metal) often becomes the thermal protection bottleneck of the electric drive system. In this case, due to the limitations of plastic worm gears in withstanding high temperatures, the worm gear is often considered a key component to focus on during thermal protection design, and corresponding thermal protection measures can be designed to trigger a thermal protection mechanism when the temperature of the worm gear exceeds a thermal protection temperature threshold, in order to prevent thermal damage due to overheating.
[0032] However, as mentioned earlier, in existing known designs, the thermal protection temperature threshold for electric drive systems is typically set to a constant value. In this case, the thermal protection temperature threshold obviously cannot vary for different operating conditions of the electric drive system in actual operation. Under different operating conditions, the selected components of interest actually exhibit different heat resistance performances. Therefore, using a constant thermal protection temperature threshold cannot fully adapt to the actual operating conditions of the electric drive system, nor can it fully utilize the maximum heat resistance potential of the electric drive system, nor achieve the desired optimal effect.
[0033] On the other hand, after extensive and thorough research, the inventors of this application have recognized and discovered that under different operating conditions and different preset thermal protection temperature thresholds, there is a certain relationship (i.e., a certain regularity) between the speed (i.e., rotational speed, and in the case of a wiper, the wiping speed of the wiper arm) and torque (also referred to as torque or torque force) of the drive motor of the electric drive system. In this case, if the predetermined relationship between the speed and torque of the drive motor under different operating conditions and different preset thermal protection temperature thresholds is obtained in advance (e.g., through experimental simulation) and used as reference data or basis, and combined with the speed and torque of the drive motor obtained in real time, an optimized thermal protection temperature threshold that is suitable for it can be calculated and determined by data processing methods such as fitting or interpolation, thereby effectively overcoming the problems or defects in the aforementioned known technologies.
[0034] It is based on the above background, and combined with Figure 1 As can be seen, this application proposes an improved motor control method, which can control the operation of the drive motor of an electric drive system based on a predetermined thermal protection temperature threshold to provide the required thermal protection function. The motor control method includes the following steps:
[0035] In response to the start of the drive motor, the temperature of selected components of interest in the electric drive system is acquired (e.g., by measurement and / or calculation as known in the art); and
[0036] The temperature of the selected component of interest is compared with the thermal protection temperature threshold, and the operating state of the drive motor is changed based on the comparison result. When the temperature of the selected component of interest exceeds the thermal protection temperature threshold, a thermal protection mechanism is triggered to stop the operation of the drive motor or adjust its operating parameters, thereby preventing thermal damage to the selected component of interest due to excessive temperature.
[0037] Specifically, before comparing the acquired temperature of the selected component of interest with the thermal protection temperature threshold, the thermal protection temperature threshold is determined in real time through the following thermal protection temperature threshold determination process, which includes:
[0038] The data acquisition step S10 involves acquiring, in response to the start of the drive motor, the speed and torque of the drive motor during operation in real time (e.g., by measurement and / or calculation as known in the art): and
[0039] The thermal protection temperature threshold determination step S20 involves using the acquired speed and torque of the drive motor and calculating and determining the thermal protection temperature threshold based on a pre-stored predetermined relationship between the speed and torque of the drive motor under different operating conditions and different preset thermal protection temperature thresholds.
[0040] It should be noted that, in this application, the process of determining the thermal protection temperature threshold will be performed after the drive motor is started (e.g., after the drive motor is detected to start running), and can be performed before or after the step of obtaining the temperature of the selected components of interest in the electric drive system (or even simultaneously). It can automatically determine the thermal protection temperature threshold (i.e., the ideal or optimal thermal protection temperature threshold) adapted to the electric drive system using the operating data of the drive motor of the electric drive system (e.g., speed and torque).
[0041] As can be seen from the above description, the core or essence of this application lies in the ability to predetermine the predetermined relationship (i.e., construct a functional relationship) between the speed and torque of the drive motor under different operating conditions and different preset thermal protection temperature thresholds, and then dynamically determine the ideal or optimal thermal protection temperature threshold based on this relationship, for example, by combining the speed and torque of the drive motor (corresponding to the load) obtained in real time. In other words, by adopting the motor control method of this application (especially the thermal protection temperature threshold determination process therein), the corresponding thermal protection temperature thresholds can be dynamically and intelligently adjusted according to the speed and torque of the drive motor obtained in real time to make them adapt to each other, thereby fully utilizing the maximum heat resistance potential of the electric drive system and achieving the best thermal protection effect.
[0042] According to an advantageous and feasible embodiment of this application, the thermal protection temperature threshold determination step S20 can be performed periodically at predetermined time intervals, wherein the time intervals can be determined based on experience or experiments and can be appropriately adjusted according to specific circumstances or actual needs.
[0043] According to an advantageous and feasible embodiment of this application, before performing the thermal protection temperature threshold determination process (in particular, before the drive motor is started, for example, before the vehicle is started in the case of use in a vehicle, but not limited thereto), the predetermined relationship between the speed and torque of the drive motor can be predetermined by simulating (e.g., experimentally simulating) the operation of the drive motor under different operating conditions and different preset thermal protection temperature thresholds, and can be calibrated (or standardized) as needed.
[0044] More specifically, in the process of determining the aforementioned predetermined relationship, the predetermined relationship between the speed and torque of the drive motor under different operating conditions and different preset thermal protection temperature thresholds can be obtained by simulating the operation of the drive motor under different operating conditions and different preset thermal protection temperature thresholds (especially under specific operating conditions and extreme thermal protection temperature thresholds). This allows the establishment of a corresponding relationship model or mapping relationship and its storage (e.g., in the memory of the control unit), thereby laying the foundation for subsequent processes and providing data support (or reference).
[0045] As previously stated, according to an advantageous and feasible embodiment of this application, the motor control method can be a motor control method for an electric drive system of a wiper, the wiper including a transmission mechanism connected to a drive motor of the electric drive system and a wiper arm connected to the transmission mechanism, so as to drive a wiper blade connected to the wiper arm to achieve the required wiping action under the driving action of the drive motor. The transmission mechanism includes a worm driven by the drive motor and a worm wheel meshing with the worm, the worm wheel being typically made of plastic (therefore also called a plastic gear or white gear) and serving as the selected component of interest, wherein a thermal protection temperature threshold is determined to trigger a thermal protection mechanism when the temperature of the worm wheel (which can be measured, for example, by adding a thermocouple, but is not limited to) exceeds the thermal protection temperature threshold, to, for example, reduce the speed of the drive motor (thereby reducing the wiping speed of the wiper arm), and thereby prevent the worm wheel from being damaged by excessive temperature.
[0046] In this case, according to an advantageous and feasible embodiment of the present application, in the thermal protection temperature threshold determination step S20, the predetermined relationship between the speed and torque of the drive motor may include a first predetermined relationship and a second predetermined relationship. The first predetermined relationship may be the predetermined relationship between the speed and torque of the drive motor measured when scraping is performed under ideal dry conditions and the minimum acceptable temperature threshold Cmin under this condition is taken as the first preset thermal protection temperature threshold. The second predetermined relationship may be the predetermined relationship between the speed and torque of the drive motor measured when scraping is performed under ideal wet conditions and the maximum acceptable temperature threshold Cmax under this condition is taken as the second preset thermal protection temperature threshold.
[0047] In this case, this application can combine the current speed and torque of the drive motor when it is running in actual working environments with different wetting conditions (humidity), and based on the predetermined relationship between the speed and torque of the drive motor obtained previously under ideal dry conditions and ideal humid conditions, to automatically determine the thermal protection temperature threshold adapted to the current working conditions, so as to achieve the best thermal protection effect and improve the thermal performance of the electric drive system.
[0048] In addition, according to an advantageous and feasible embodiment of this application, the first predetermined relationship and the second predetermined relationship can be obtained by recording a certain number of data points (i.e., typical values measured when scraping under ideal dry and ideal wet conditions, respectively) and fitting these data points (which can be characterized and stored, for example, by polynomials, graphs, lines, tables, etc.), wherein each data point corresponds to the speed and torque of the drive motor when the thermal protection mechanism is triggered.
[0049] Moreover, according to an advantageous and feasible implementation of this application, at least one of the first predetermined relationship and the second predetermined relationship can be obtained by fitting a linear regression or a piecewise function, but is obviously not limited thereto.
[0050] More specifically, such as Figure 2 As shown, according to an advantageous and feasible embodiment of this application, in a rectangular coordinate system with the speed V of the drive motor as the abscissa and the torque T of the drive motor as the ordinate, the first predetermined relationship can be fitted into a first straight line L1 by linear regression and can be expressed by the following first equation: T = a1 × V + b1, and the second predetermined relationship can be fitted into a second straight line L2 by linear regression and can be expressed by the following second equation: T = a2 × V + b2, where a1 and a2 represent the slopes of the first straight line L1 and the second straight line L2, respectively, and b1 and b2 represent the intercepts of the first straight line L1 and the second straight line L2 on the ordinate, respectively.
[0051] Alternatively, such as Figure 3 As shown, according to an advantageous and feasible embodiment of this application, in a Cartesian coordinate system with the speed V of the drive motor as the abscissa and the torque T of the drive motor as the ordinate, the first predetermined relationship can be fitted as a piecewise function. Figure 3 The broken line shown in the upper middle section indicates that the second predetermined relationship can be fitted using a piecewise function. Figure 3 The broken line shown in the lower middle section.
[0052] It should be noted that, in Figure 2 , Figure 3 In the process of obtaining the first predetermined relationship and the second predetermined relationship as shown in the figure (also known as the motor calibration or standardization process), with... Figure 2 The first straight line L1 or Figure 3 The dot corresponding to the fold line on the upper side represents the data point measured under ideal dry conditions (i.e., dry shaving) with the minimum acceptable temperature threshold Cmin as the first preset thermal protection temperature threshold. It exhibits a relatively high torque value corresponding to different motor speeds; and... Figure 2 The second straight line L1 or Figure 3 The dots corresponding to the broken lines on the lower side are data points measured when scraping under ideal wet conditions (i.e., wet scraping) and the maximum acceptable temperature threshold Cmax is used as the second preset thermal protection temperature threshold. They show relatively low torque values corresponding to different motor speeds.
[0053] In addition, it should be noted that during the application of the motor control method, the first predetermined relationship and / or the second predetermined relationship can be appropriately adjusted according to actual needs (e.g., to avoid potential thermal damage to the motor of the electric drive system and to reduce errors, etc.). For example, the first straight line L1 and / or the second straight line L2 can be translated (moved up or down) to provide more stringent or more suitable thermal protection.
[0054] like Figure 1 As shown, according to an advantageous and feasible embodiment of this application, based on obtaining the first equation and the second equation, the protective temperature threshold determination step S20 may include:
[0055] The intermediate variable calculation step S21 involves calculating the intermediate variable Ki based on the real-time acquired speed and torque of the drive motor, as well as the first equation and the second equation; and
[0056] The thermal protection temperature threshold setting step involves comparing the intermediate variable Ki with a given parameter value and setting the corresponding thermal protection temperature threshold based on the comparison result.
[0057] In addition, combined Figure 4 As can be seen from the content, based on obtaining the first equation and the second equation, according to an advantageous and feasible implementation of this application, in the intermediate variable calculation step S21, the intermediate variable Ki can be calculated by linear interpolation according to the following formula:
[0058]
[0059] Wherein, Vi represents the speed of the drive motor acquired in real time (e.g., obtained by measuring the motor's rotational speed through a speed sensor, but not limited thereto), and Ti represents the torque of the drive motor acquired in real time (e.g., obtained by measuring the motor's current and performing appropriate calculations, but not limited thereto).
[0060] More specifically, such as Figure 4 As shown, based on the real-time acquisition of the speed and torque of the drive motor (corresponding to data point Z, which corresponds to a certain working condition of the motor during normal operation and has speed Vi and torque Ti), the intermediate variable Ki can be calculated by linear comparison using the previously acquired first equation (corresponding to the first straight line L1) and second equation (corresponding to the second straight line L2). The process or design principle of obtaining the calculation formula of the intermediate variable Ki is as follows:
[0061]
[0062] like Figure 1 As shown, after calculating the intermediate variable Ki (i.e., intermediate variable calculation step S21), according to an advantageous and feasible embodiment of this application, the thermal protection temperature threshold setting step may include:
[0063] The first comparison and judgment step S22 involves comparing the intermediate variable Ki with the value 1 and giving the first comparison and judgment result, i.e., comparing and judging whether the intermediate variable Ki is greater than or equal to 1.
[0064] First thermal protection temperature threshold setting step S23, wherein if the first comparison and judgment result is determined to be Ki≥1 (i.e., the result of the first comparison and judgment step S22 is Y), the maximum acceptable temperature threshold Cmax is set as the thermal protection temperature threshold (i.e., if Ki≥1, then the thermal protection temperature threshold can be set as the maximum acceptable temperature threshold Cmax); and
[0065] The second comparison and judgment step S24 and the subsequent thermal protection temperature threshold setting step, wherein when the first comparison and judgment result is determined to be Ki<1 (that is, the result of the first comparison and judgment step S22 is N), the intermediate variable Ki is compared with the value 0 and a second comparison and judgment result is given, that is, the intermediate variable Ki is compared and judged to see if it is less than or equal to 0, and in the subsequent thermal protection temperature threshold setting step, the corresponding thermal protection temperature threshold is set according to the second comparison and judgment result.
[0066] In addition, such as Figure 1 As shown, according to an advantageous and feasible embodiment of this application, the subsequent thermal protection temperature threshold setting step may include:
[0067] The second thermal protection temperature threshold setting step S25, wherein if the second comparison and judgment result is determined to be Ki≤0 (i.e., the result of the second comparison and judgment step S24 is Y), the minimum acceptable temperature threshold Cmin is set as the thermal protection temperature threshold (i.e., if Ki≤0, it means that the thermal protection temperature threshold can be set as the minimum acceptable temperature threshold Cmin); and
[0068] In the third thermal protection temperature threshold setting step S26, when the second comparison and judgment result is determined to be Ki>0 (i.e., the result of the second comparison and judgment step S24 is N), the intermediate thermal protection temperature threshold Ci, which is between the maximum acceptable temperature threshold Cmax and the minimum acceptable temperature threshold Cmin, is set as the thermal protection temperature threshold (i.e., if Ki>0, it means that the thermal protection temperature threshold can be set by interpolation and is between the maximum acceptable temperature threshold Cmax and the minimum acceptable temperature threshold Cmin).
[0069] from Figure 5 As can be seen from this, according to an advantageous and feasible embodiment of this application, the intermediate thermal protection temperature threshold Ci is determined by linear interpolation according to the following formula:
[0070] Ci = Ki × (Cmax - Cmin) + Cmin.
[0071] According to an advantageous and feasible implementation of this application, and as an example, the minimum acceptable temperature threshold Cmin may be in the range of 80°C-95°C, and the maximum acceptable temperature threshold Cmax may be in the range of 110°C-125°C, but is obviously not limited thereto.
[0072] It should be noted that the above temperature range applies to electric drive systems in windshield wipers for wiping vehicle windshields, and depends primarily on the material of the transmission mechanism (e.g., plastic gears) in the electric drive system, but is not limited thereto. Furthermore, the above temperature ranges can be determined experimentally or empirically, and can be appropriately varied or adjusted according to actual needs.
[0073] Therefore, this application proposes a novel motor control method (in particular, a novel thermal protection temperature determination process therein), which can utilize the current operating data (e.g., speed and torque) of the drive motor of the electric drive system and, based on pre-stored predetermined relationships between the speed and torque of the drive motor under different operating conditions and different preset thermal protection temperature thresholds, determine in real time and automatically the thermal protection temperature threshold adapted to the electric drive system (in particular, adapted to its current operating condition), thereby obtaining an optimized thermal protection temperature threshold. This method can achieve significant beneficial effects such as enhancing adaptability to the operating environment and actual working conditions, improving the reliability of system operation, and maximizing the heat resistance potential of system components.
[0074] In particular, as can be seen from the foregoing description, the motor control method of this application, while effectively overcoming the defects or deficiencies in the prior art, has the following substantial features or advantages:
[0075] This application combines the torque and speed of the drive motor of the electric drive system (i.e., takes into account) to automatically determine the optimal thermal protection temperature threshold applicable to the electric drive system, thereby enabling precise control of the thermal protection process of the electric drive system, maximizing the heat resistance potential of system components, and providing the best thermal protection performance.
[0076] According to this application, different thermal protection temperature thresholds can be automatically output according to different motor operating conditions (i.e., different torques and speeds). For example, at the same speed, when the motor is running at a higher torque / load, a relatively lower thermal protection temperature threshold can be used, while at the same torque / load, when the motor is running at a lower speed, a relatively higher thermal protection temperature threshold can be used, but not limited thereto. This can significantly enhance the adaptability to the operating environment and actual working conditions.
[0077] In this application, the determination of the thermal protection temperature threshold is not affected by ambient temperature, motor voltage, etc., thus ensuring the stability and reliability of the electric drive system in a simple way; and
[0078] For applications in electric drive systems of wipers, the motor control method of this application can automatically provide the optimal thermal protection temperature threshold based on the motor torque and speed under different wiping environment wetting conditions. This can effectively avoid adverse phenomena such as repeated changes or irregular fluctuations in the wiping speed of the wiper arm (or wiper blade), thereby significantly improving wiping stability and system durability, and providing the expected system thermal protection performance to fully meet customer requirements.
[0079] Furthermore, the motor control method of this application can be applied, for example, to the electric drive system of wipers, particularly to wiper systems of REEVs (Range Extended Electric Vehicles) and PHEVs (Plug-in Hybrid Electric Vehicles), but is obviously not limited thereto.
[0080] Furthermore, it is obvious that, as mentioned above, the exemplary embodiments and their specific steps described in conjunction with the accompanying drawings are provided by way of illustration only to facilitate understanding of this application, and are not intended to limit this application. For those skilled in the art, without departing from the basic principles or technical concept of this application, the number, order, and specific content of each step in the embodiments shown in the figures can be appropriately increased, decreased, or adjusted according to specific applications or actual needs (for example, the judgment conditions and specific settings of various parameter values in each step can be appropriately changed or adjusted). Moreover, regarding some contents not described in detail in this application (e.g., implementation methods of existing known thermal protection mechanisms, more details of some data processing methods in the motor control method of this application, etc.), those skilled in the art can make specific designs or selective applications based on known technologies and common knowledge in the field, combined with specific needs. For the sake of brevity, these will not be elaborated here.
[0081] It should be understood that in this application, the terms "first," "second," etc., are used only to distinguish one element / relationship / state / step from another element / relationship / state / step, etc., and do not imply any limitation on this application.
[0082] In accordance with the above-described motor control method, this application also proposes a related (in other words, corresponding) control unit, which may include:
[0083] Processor; and
[0084] A memory storing computer programs / instructions, which, when executed by the processor, implement the motor control method as described above.
[0085] Obviously, the motor control method of this application can be executed by the control unit of this application, and the various technical features, specific details, and technical effects described for the method also apply to the control unit. Furthermore, each step and technical detail of the method described above can be stored in the control unit in software form and can be implemented in a field or remote control manner by means of software or a combination of software and hardware. In addition, the control unit of this application can be integrated into various existing control units; for example, in the case of an electric drive system for windshield wipers in a vehicle, it can be integrated into the vehicle control unit, but it is obviously not limited to this.
[0086] In addition, according to another aspect of this application, a computer program product is also proposed, which includes a computer program (or instructions) that, when executed by a processor, can implement the motor control method as described above.
[0087] The present application has been described in detail above with reference to specific embodiments. It is obvious that, as stated above, the description and embodiments shown in the accompanying drawings should be understood as exemplary and not as limiting the present application. Those skilled in the art can make various modifications or alterations without departing from the spirit of the present application. Obviously, these modifications or alterations do not depart from the scope of the present application.
Claims
1. A motor control method, which controls the operation of a drive motor of an electric drive system based on a predetermined thermal protection temperature threshold to provide the required thermal protection function, the motor control method comprising the following steps: In response to the start of the drive motor, the temperature of a selected component of interest in the electric drive system is obtained; as well as The temperature of the selected component of interest is compared with the thermal protection temperature threshold, and the operating state of the drive motor is changed based on the comparison result. When the temperature of the selected component of interest exceeds the thermal protection temperature threshold, a thermal protection mechanism is triggered to stop the operation of the drive motor or adjust its operating parameters, thereby preventing thermal damage to the selected component of interest due to excessive temperature. Specifically, before comparing the acquired temperature of the selected component of interest with the thermal protection temperature threshold, the thermal protection temperature threshold is determined in real time through the following thermal protection temperature threshold determination process, which includes: The data acquisition step (S10) is performed, wherein, in response to the start of the drive motor, the speed and torque of the drive motor during operation are acquired in real time: and The thermal protection temperature threshold determination step (S20) involves using the acquired speed and torque of the drive motor and calculating and determining the thermal protection temperature threshold based on a pre-stored predetermined relationship between the speed and torque of the drive motor under different operating conditions and different preset thermal protection temperature thresholds.
2. The motor control method according to claim 1, wherein, The thermal protection temperature threshold determination step (S20) is performed periodically at predetermined time intervals; Before performing the thermal protection temperature threshold determination process, the predetermined relationship between the speed and torque of the drive motor is predetermined or calibrated by simulating the operation of the drive motor under different working conditions and different preset thermal protection temperature thresholds. and / or The motor control method is a motor control method for an electric drive system of a wiper. The wiper includes a transmission mechanism connected to a drive motor of the electric drive system and a wiper arm connected to the transmission mechanism, so as to drive the wiper blade connected to the wiper arm to achieve the required wiping action under the driving action of the drive motor. The transmission mechanism includes a worm driven by the drive motor and a worm wheel meshing with the worm. The worm wheel is made of plastic and serves as the selected component of concern. The thermal protection temperature threshold is determined to trigger a thermal protection mechanism when the temperature of the worm wheel exceeds the thermal protection temperature threshold, thereby reducing the speed of the drive motor and preventing the worm wheel from being damaged by heat due to excessive temperature.
3. The motor control method according to claim 2, wherein, When the motor control method is a motor control method for an electric drive system of a wiper, in the thermal protection temperature threshold determination step (S20), the predetermined relationship between the speed and torque of the drive motor includes a first predetermined relationship and a second predetermined relationship. The first predetermined relationship is the predetermined relationship between the speed and torque of the drive motor measured when wiping is performed under ideal dry conditions and the minimum acceptable temperature threshold Cmin under these conditions is taken as the first preset thermal protection temperature threshold. The second predetermined relationship is the predetermined relationship between the speed and torque of the drive motor measured when wiping is performed under ideal wet conditions and the maximum acceptable temperature threshold Cmax under these conditions is taken as the second preset thermal protection temperature threshold.
4. The motor control method according to claim 3, wherein, The first predetermined relationship and the second predetermined relationship are obtained by recording a certain number of data points and fitting these data points. Each data point corresponds to the speed and torque of the drive motor when the thermal protection mechanism is triggered. At least one of the first predetermined relationship and the second predetermined relationship is obtained by fitting with a linear regression or a piecewise function.
5. The motor control method according to claim 4, wherein, In a Cartesian coordinate system with the speed V of the drive motor as the abscissa and the torque T of the drive motor as the ordinate, the first predetermined relationship is fitted into a first straight line L1 by linear regression and expressed by the following first equation: T = a1 × V + b1, and the second predetermined relationship is fitted into a second straight line L2 by linear regression and expressed by the following second equation: T = a2 × V + b2, where a1 and a2 represent the slopes of the first straight line L1 and the second straight line L2, respectively, and b1 and b2 represent the intercepts of the first straight line L1 and the second straight line L2 on the ordinate, respectively.
6. The motor control method according to claim 5, wherein, The step of determining the thermal protection temperature threshold (S20) includes: The intermediate variable calculation step (S21) involves calculating the intermediate variable Ki based on the real-time acquired speed and torque of the drive motor, as well as the first and second equations; and The thermal protection temperature threshold setting step involves comparing the intermediate variable Ki with a given parameter value and setting the corresponding thermal protection temperature threshold based on the comparison result. In the intermediate variable calculation step (S21), the intermediate variable Ki is calculated using linear interpolation according to the following formula: Where Vi represents the speed of the drive motor as obtained in real time, and Ti represents the torque of the drive motor as obtained in real time.
7. The motor control method according to claim 6, wherein, The thermal protection temperature threshold setting step includes: The first comparison and judgment step (S22) involves comparing the intermediate variable Ki with the value 1 and giving a first comparison and judgment result, i.e. comparing and judging whether the intermediate variable Ki is greater than or equal to 1. The first thermal protection temperature threshold setting step (S23) involves setting the maximum acceptable temperature threshold Cmax as the thermal protection temperature threshold when the first comparison and judgment result is determined to be Ki≥1; and In the second comparison and judgment step (S24) and the subsequent thermal protection temperature threshold setting step, if the first comparison and judgment result is determined to be Ki < 1, the intermediate variable Ki is compared with the value 0 and a second comparison and judgment result is given, that is, whether the intermediate variable Ki is less than or equal to 0 is compared and judged. In the subsequent thermal protection temperature threshold setting step, the corresponding thermal protection temperature threshold is set according to the second comparison and judgment result. The subsequent thermal protection temperature threshold setting step includes: The second thermal protection temperature threshold setting step (S25) involves setting the minimum acceptable temperature threshold Cmin as the thermal protection temperature threshold when the second comparison and judgment result is determined to be Ki≤0; and The third thermal protection temperature threshold setting step (S26) involves setting the thermal protection temperature threshold Ci, which is between the maximum acceptable temperature threshold Cmax and the minimum acceptable temperature threshold Cmin, as the thermal protection temperature threshold when the second comparison and judgment result is determined to be Ki>0.
8. The motor control method according to claim 7, wherein, The intermediate thermal protection temperature threshold Ci is determined by linear interpolation according to the following formula: Ci = Ki × (Cmax - Cmin) + Cmin.
9. A control unit, comprising: processor; as well as A memory storing a computer program / instruction, which, when executed by the processor, implements the motor control method as described in any one of claims 1-8.
10. A computer program product comprising a computer program that, when executed by a processor, implements the motor control method as described in any one of claims 1-8.